Also, the 84-87 Sabre was available with adjustable bars, those were about 2" taller than the nighthawk bars, and the 1983 Magna and some 84 Magnas were available with adjustable bars, those are 4" taller than the Nighthawk bars, but they cost a pretty penny as that was a rare option on those bikes.

Another thing to consider (if you already have tubular bar adaptors) is to look for handlebars from mid-1980's Honda Nighthawk S. They have an adjustment capability at the lower knuckle that allows pull-back changes. This is what I did: